CN-122012847-A - Semisteel steelmaking method of SPA-H weather-resistant steel by using slag making under furnace

Abstract

The invention discloses a semisteel steelmaking method of SPA-H weather-resistant steel by using slag formation under a steelmaking furnace, wherein semisteel is smelted in a converter, slag formation is carried out by adding the slag formation under the steelmaking furnace as slag forming materials in the blowing process, the slag formation under the steelmaking furnace is added in two batches, the first batch is added at the moment of blowing oxygen step to 40% -50%, the addition amount is 70% -80% of the total mass, the second batch is added at the moment of blowing oxygen step to 60% -70%, the addition amount is 20% -30% of the total mass, the oxygen lance position is controlled according to a high-low mode in the blowing process, the early lance position is 1.7-1.8 m, the middle lance position is 1.55-1.65 m, and the later lance position is 1.4-1.45 m. The method can safely and stably use the slag in the steelmaking process, control the dephosphorization rate in a proper range, realize the recycling of the slag in the steelmaking process, avoid the waste of resources, reduce the steelmaking production cost, and has the characteristics of good safety, low cost, energy conservation and environmental protection.

Inventors

• YU HAI
• ZHANG MINGBO
• FANG MING
• GAO JIANGUO
• SONG HUIQIANG
• BAO QINGFENG
• JIA ZENGLI
• ZHANG ZIJIAN

Assignees

• 承德钒钛新材料有限公司
• 承德钢铁集团有限公司
• 河钢股份有限公司承德分公司

Dates

Publication Date

20260512

Application Date

20260122

Claims (5)

1. 1. A semisteel steelmaking method of SPA-H weather-resistant steel by using slag formation under a furnace is characterized in that semisteel is smelted in a converter, slag formation is carried out by adding slag from the steel-making furnace as slag forming materials in the blowing process, the slag from the steel-making furnace is added in two batches, the first batch is added at the time of blowing oxygen step to 40% -50%, the addition amount is 70% -80% of the total mass, the second batch is added at the time of blowing oxygen step to 60% -70%, the addition amount is 20% -30% of the total mass, the oxygen lance position is controlled according to a high-low mode in the blowing process, the early lance position is 1.7-1.8 m, the middle lance position is 1.55-1.65 m, and the later lance position is 1.4-1.45 m.
2. 2. The semisteel steelmaking method of SPA-H weathering steel using slag formation under a furnace of claim 1, wherein the total amount of slag addition under the steelmaking furnace is 4000-6000 kg.
3. 3. The semisteel steelmaking method of SPA-H weathering steel using slag formation under a furnace according to claim 1, wherein oxygen pressure in the oxygen blowing process is 0.75-0.85 mpa, and oxygen supply strength is 3.0-3.6 Nm 3 /(t.min).
4. 4. The semisteel steelmaking method of SPA-H weathering steel by using slag formation under a converter as claimed in claim 1, wherein the end temperature of converter smelting is 1610-1630 ℃.
5. 5. A semisteel production method of SPA-H weathering steel using slag formation under a furnace according to any of claims 1-4, characterized in that the slag composition and mass content under the steel-making furnace are satisfied with CaO >35%, siO 2 <8%, mgO >15%, P <5%, S <1%.

Description

Semisteel steelmaking method of SPA-H weather-resistant steel by using slag making under furnace Technical Field The invention relates to a steelmaking method, in particular to a semisteel steelmaking method of SPA-H weather-resistant steel by slag making under a furnace. Background The semisteel is an intermediate product formed after the molten iron is subjected to the converter vanadium extraction process, and compared with the molten iron, the semisteel has low content of elements such as silicon, manganese and carbon, so that slag is not easy to dissolve in the semisteel steelmaking process, and the dephosphorization efficiency is low. In the traditional process, the slag is generally used for external-commission magnetic separation processing or directly used as waste discharge, and when processing cost and transportation cost are generated, the iron element and MgO in the slag are not fully utilized, so that resource waste is caused. Because most of slag in a steelmaking furnace belongs to premelted materials and contains part of ferric oxide, the slag is a substance favorable for melting slag, the slag is easily blown out in the blowing process of the converter by simply using the slag in the furnace, potential safety hazards are generated, and excessive slag melting accelerates dephosphorization reaction efficiency, so that a large amount of ferrophosphorus is alloyed to generate cost waste. Disclosure of Invention The invention aims to solve the technical problem of providing a safe and stable semisteel steelmaking method of SPA-H weathering steel by using slag making under a furnace. The technical scheme includes that semisteel is smelted in a converter, slag is added from a steelmaking furnace as slag forming materials in the converting process, the slag is added in two batches, the first batch is added at the beginning of converting oxygen steps of 40% -50%, the adding amount is 70% -80% of the total mass, the second batch is added at the beginning of converting oxygen steps of 60% -70%, the adding amount is 20% -30% of the total mass, in the converting process, the lance position of an oxygen lance is controlled according to a high-low mode, the lance position in the early stage of the oxygen converting process is 1.7-1.8 m, the lance position in the middle stage is 1.55-1.65 m, and the lance position in the later stage is 1.4-1.45 m. Further, the total adding amount of the slag discharging single furnace of the steelmaking furnace is 4000-6000 kg. Further, the oxygen pressure in the oxygen blowing process is 0.75-0.85 mpa, and the oxygen supply strength is 3.0-3.6 Nm 3/(t.min). Further, the end temperature of converter smelting is 1610-1630 ℃. Further, the slag ingredients and mass contents of the steel-making furnace are more than 35% of CaO, more than 8% of SiO 2%, more than 15% of MgO, less than 5% of P and less than 1% of S. The technical scheme has the beneficial effects that the slag discharging of the steelmaking furnace is used for replacing all conventional slag-making materials, the slag discharging of the steelmaking furnace is added into the converter in batches in the blowing process of the converter through the high-level bin, the position of the blowing gun is matched for optimization adjustment, the direct oxygen supply duty ratio is improved to the maximum extent, excessive melting of the slag is avoided, dephosphorization is carried out to a certain extent while the decarburization process is not influenced, and converter explosion is avoided, so that the slag discharging of the steelmaking furnace can be safely and stably used in the steelmaking process, the dephosphorization rate is controlled in a proper range, and the purposes of producing SPA-H weathering steel safely and at low cost are achieved. The invention realizes the cyclic utilization of slag in the steelmaking process of the steelmaking furnace, avoids the resource waste, is beneficial to reducing the slag making cost in the SPA-H weather-resistant steel smelting process, reduces the steelmaking production cost, reduces the steelmaking waste discharge and is beneficial to environmental protection. The invention has the characteristics of good safety, low cost, energy conservation and environmental protection. Detailed Description The present invention will be described in further detail with reference to the following embodiments. The semisteel steelmaking method of SPA-H weathering steel by using slag making under a converter uses semisteel as a raw material to smelt in the converter. The semisteel comprises, by mass, 3.0-3.3% of C, 0.140% of P, 0.1% of Si, 0.1% of Ti, and the balance of iron and other unavoidable elements. The converter smelting is characterized in that steel-making furnace slag is added to replace all conventional slag making materials in the blowing process to be used as slag making materials for slag making, the furnace slag making is a mixture and mainly comprises steel slag scattered in